1. Technical Field
The present invention relates to an industrial machine using a power converter.
2. Description of the Related Art
In recent construction machines including a power shovel or a crane, a hybrid type of a hydraulic motor and an AC motor is used as a power source of an upper swivel body. The hybrid type swiveling power source assists a hydraulic motor with the AC motor during acceleration of the upper swivel body, performs a regenerative operation with an AC motor during deceleration, and charges a battery with power generation energy. The pertinent technique is disclosed in the related art. Additionally, for example, a power converter for driving the electric motor is also mounted in industrial machines other than the construction machines, for example, a forklift and a forging press machine.
The power converter (inverter) for driving the AC motor includes a plurality of switching elements that are provided for respective phases of the AC motor, a controller that generates a control signal modulated according to the target torque (or target rotation speed) of the AC motor, and a driver that drives the plurality of switching elements on the basis of the control signal.